Recently, a quadruped robot apparatus which behaves in response to an instruction given by the user of the robot apparatus and adaptively to the surrounding environment and the like has been developed by the Applicant of the present invention, and commercially available. Such a robot apparatus has installed therein a CCD (charge coupled device) camera and microphone. Assessing the environmental condition and determining whether or not an instruction has been given by the user, based on an environment captured by the CCD camera, and a command voice from the user or an ambient sound, picked up by the microphone, the robot apparatus autonomously decides how to behave, and does the behavior, based on the results of assessment and determination.
However, since the robot apparatuses of the above type are normally used in the ordinary dwellings in which there exist many obstacles to the robot apparatus such as doorsills, power cords and the like, some measures have to be worked out to prevent the robot apparatus from easily tumbling while walking in such an environment. To this end, some solutions have been proposed. One of such solutions is a quadruped robot apparatus which controls its own behavior by detecting an obstacle based on image signals from the CCD camera and causing itself to detour around the obstacle based on the result of detection. Another solution is to provide a special force sensor in each of leg blocks of the robot apparatus, and detect, based on an output from the sensor, whether the robot apparatus has collided with any obstacle.
In the robot apparatus using the CCD camera, however, detecting an obstacle based on the image signals from the CCD camera takes a long time and it is not possible to recognize an obstacle, if any, at any high success rate. Also, the sensors provided in the leg blocks add to the number of parts of the robot apparatus whose construction will thus be complicated and production cost and weight will be increased.
Further, in case such a robot apparatus is provided with a plurality of sensors in predetermined positions, it will be able to detect an obstacle and behave as specified (sitting down, for example) correspondingly to a pressed one of the sensors. Therefore, provision of more sensors on the robot apparatus will permit the user of the robot apparatus to enjoy higher-level interactions with his or her robot apparatus.
However, in case such touch sensors are provided in predetermined positions on the robot apparatus, touch can only be detected in the limited positions and thus the interaction of the robot apparatus with its user will be limited. For example, use of advanced sensors for detection of a direction in which a force has been applied to the robot apparatus will also lead to a complicated construction, and an increased production cost and weight, of the robot apparatus. Also, such sensors cannot be provided at all portions of the robot apparatus.